ZQ calibration method of memory device with shared ZQ pin

Abstract

A memory device configured to perform a ZQ calibration method may include a first die and a second die that share a resistor connected to a ZQ pin. The first die may be configured to perform a first calibration operation using the resistor in response to a ZQ calibration command applied from outside of the memory device. The first die may be configured to generate a ZQ flag signal after the firstcalibration operation ends and perform a second calibration operation. The second die may be configured to perform the first calibration operation in response to the ZQ flag signal and perform a second calibration after the first calibration operation of the second die ends.

Description

[0001] Cross References to Related Applications [0002] This application claims priority from Korean Patent Application No. 10-2016-0162912 filed in the Korean Intellectual Property Office on December 1, 2016, the entire disclosure of which is incorporated herein by reference. technical field [0003] Various exemplary embodiments relate to semiconductor devices, and more particularly, to ZQ calibration methods for maintaining calibration operation times in memory devices having shared ZQ pins. Background technique [0004] The swing width of signals is being reduced in order to minimize the transmission time of signals for interfaces between semiconductor devices. As the swing width of the signal decreases, the influence of external noise on the semiconductor device increases, and signal reflection, possibly caused by impedance mismatch in the interface, can be a serious problem. In order to address impedance mismatch, a memory device includes a ZQ pin to receive a ZQ cal...

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Problems solved by technology

As the swing width of the signal decreases, the influence of external noise on semiconductor devices increase

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